The interaction effect of depressive symptoms and inflammation on the occurrence of cardiovascular diseases

Whether there was an interaction effect between depressive symptoms and inflammation on the occurrence of cardiovascular diseases (CVDs) was unclear. In this cross-sectional study, 3346 participants in the National Health and Nutrition Examination Survey (NHANES) were included. Multivariable regression analysis was performed to explore the associations of depressive symptoms or inflammation with CVDs. The attributable proportion of interaction (API), and synergy index (SI) were applied for evaluating the statistical significance of the interaction effect. Depressive symptoms were associated with 2.31-fold risk of CVDs [odds ratio (OR) = 2.31, 95 % confidence interval (CI): 1.47–3.62). The increased risk of CVDs was observed in people with neutrophil to lymphocyte ratio (NLR) ≥1.88 group (OR = 1.36, 95%CI: 1.01–1.85) and neutrophil/[white blood cell (WBC)-neutrophil] ≥1.35 (OR = 1.52, 95%CI: 1.12–2.07) after adjusting for confounders. The interaction effect of depressive symptoms and high NLR on the risk of CVDs was statistically significant with an OR value of 2.60 (95%CI: 1.43–4.70) compared to low NLR and no depressive symptoms group after adjusting for confounders. The API was 0.66 (95%CI: 0.44–0.89) and SI was 4.23 (95%CI: 2.08–8.59). The interaction effect of depressive symptoms and high neutrophil/(WBC-neutrophil) was associated with the risk of CVDs compared to low neutrophil/(WBC-neutrophil) and no depressive symptoms group (OR = 3.59, 95%CI: 2.00–6.45). The API was 0.78 (95%CI: 0.63–0.93) and SI was 6.75 (95%CI: 3.55–12.82). There was an interaction effect of depressive symptoms and inflammation on the occurrence of CVDs.